You will get better performance from fibre channel than scsi. 2 x 2 gig Fibre Channel cards load balanced with something like EMC's Power path software will give good results and provide you with redundancy.
You can get excellent performance from a disk array, you over a SAN. I have had the best performance on a HP disk array over a Late model EMC SAN. (160mb/sec versus 120mb/sec) Cost of HP disk array $125K US, Cost of EMC SAN $2.5 mill US.
Spend 50% of your time sorting out your disk array.
You will need to stripe the database file over a minimum of 4 disks preferably 6 but no more than 10. Each of our databases only has one datafile.
We partition a similar table to yours into yearly databases.
create view AllData
select a,b,c from DB2002.dbo.table2002
select a,b,c from DB2003.dbo.table2003
select a,b,c from DB2004.dbo.table2004
This makes it easier to manage the databases. We can perform changes on any database while maintaining full availablity by restoring a database and changing the view to include the newly restored database. Its simpiler than filegroup backups.
It makes it easier to backup and restore as you are generally backing up and restoring a smaller database and you are likely to have the disk space to do it. We had a 400gig database that we never tested a restore on as we didn't have the disk space available on local disk let alone another server and we didn't want to restore over the top of the existing database in case it failed. It used to take 15 hours for the backup over the network, probably would have taken 30 for a restore. Not good availability.
We use litespeed, a backup and compression utility. It takes about 18 minutes to backup and 35minutes to restore a 100gig database on a 4 x 1.5gig cpu server with hyperthreading, and compresses it to 25gig. It makes it so much more manageable. We bulk load the data once a day so we backup each day.
In our case each of the tables in the yearly databases has a composite primary key and two other indexes. With 1.4 billion rows we can get any one record within 20milliseconds or less. Ranges provide similar performance. You must partition, not only from a manageablility perspective but from a performance perspective. SQL Server will not use the other tables in the partition if they don't contain data that meets the partition contraint, which ultimately means a smaller number of index pages to be traversed. Pay close attention to the query plan, you need to see index seeks not index scans.